It estimates the standardized or unstandardized indirect and direct effects
and their asymptotic sampling covariance matrix.

Usage

1

Arguments

x

A 3x3 correlation/covariance matrix or a list of
correlation/covariance matrices. Variables are
arranged as the dependent variable (y), mediator (m) and independent
variable (x)

n

Sample size or a vector of sample sizes

standardized

Logical. Whether the indirect effect is
standardized.

direct.effect

Logical. Whether the direct effect is
estimated. If it is FALSE, the direct effect is fixed at zero.

run

Logical. If FALSE, only return the mx model without running the analysis.

Details

Cheung (2009) estimated the standardized indirect effect and
its standard error with non-linear constraints. Since OpenMx does not generate standard errors when there
are non-linear constraints, Kwan and Chan's (2011) approach is used in
this function. Delta method is used to calculate the asymptotic covariance matrix.

Value

A vector (or a matrix if the input is a list of matrices) of
(standardized) indirect effect, standardized direct effect, and their
asymptotic sampling covariance matrices